The present invention generally relates to fabrication methods and resulting structures for on-chip magnetic devices. More specifically, the present invention relates to on-chip magnetic structures, e.g., a laminated magnetic inductor stack, having anisotropic magnetic layers.
Inductors, resistors, and capacitors are the main passive elements constituting an electronic circuit. Inductors are used in circuits for a variety of purposes, such as in noise reduction, inductor-capacitor (LC) resonance calculators, and power supply circuitry. Inductors can be classified as one of various types, such as a winding-type inductor or a laminated film-type inductor. Winding-type inductors are manufactured by winding a coil around, or printing a coil on, a ferrite core. Laminated film-type inductors are manufactured by stacking alternating magnetic or dielectric materials to form laminated stacks.
Among the various types of inductors the laminated film-type inductor is widely used in power supply circuits requiring miniaturization and high current due to the reduced size and improved inductance per coil turn of these inductors relative to other inductor types. A known laminated inductor configuration includes one or more magnetic or dielectric layers laminated with conductive patterns. The conductive patterns are sequentially connected by a conductive via formed in each of the layers and overlapped in a laminated direction to form a spiral-structured coil. Typically, both ends of the coil are drawn out to an outer surface of a laminated body for connection to external terminals.